Secrets PR 7 - Enable Postgres driver to use secrets for configuring SSL parameters (#18968)

* Enable Postgres driver to use secrets for configuring SSL parameters

Adding secret related properties for SSL options to Postgres driver

Move `conn-props->secret-props-by-name` to secret.clj since it's needed directly there, too

Add `us-east-2-bundle.pem` to `test-resources/certificates` for testing Postgres with SSL connectivity to our RDS instance (and a README.md explaining how it differs from the existing `ssl` directory)

Updating `value->file!` to have better logic for building the error message when the existing file is not found (for better UX from the Database admin page)

Updating frontend to support the `visible-if` value being an array, in which case any value may match the current details value, in order for that field to be visible

Adding secret related properties for SSL options to Postgres driver

Updating CircleCI config.yml to refer to the RDS instance when running Postgr...